An analysis of frequency components of shunt murmur for diagnosing shunt stenoses in hemodialysis

Abstract

Auscultation of shunt murmur is a non-invasive technique to dianose shunt stenoses in hemodialysis therapy and it is the most popular method for daily shunt administration of hemodialysis patients. From the clinical experience, high frequency components of the shunt murmur are observed when a shunt has one or more stenoses. However, this method has not been established as the objective diagnosis standard. Therefore, we tried to analyze the correlation between stenosis levels and frequency components of the shunt murmur for the basic study to establish the objective diagnosis standard of the shunt stenosis by the shunt murmur. For the purpose of this study, the frequency characteristics of some shunt murmur samples recorded at three locations of an arterio-venous fistura (AVF) were analyzed by using discrete wavelet transformation at the beginning. Secondly, we conducted a significant difference test of average values of correlation coefficients between stenosis levels. The experimental results revealed that we could observe the significant differences of frequency levels of the shunt murmur between stenosis levels especially at the anastomosis spot and the stenosis spot of the shunt, while the significant differences could not be observed at the down stream of the stenosis spot. © 2009 Springer-Verlag.